Dengue and Zika virus infection patterns vary among Aedes aegypti field populations from Belo Horizonte, a Brazilian endemic city

Abstract

Dengue virus (DENV) and Zika virus (ZIKV) belong to the same viral family, the Flaviviridae. They cause recurring threats to the public health systems of tropical countries such as Brazil. The primary Brazilian vector of both viruses is the mosquito Aedes aegypti. After the mosquito ingests a blood meal from an infected person, the viruses infect and replicate in the midgut, disseminate to secondary tissues and reach the salivary gland (SG), where they are ready to be transmitted to a vertebrate host. It is thought that the intrinsic discrepancies among mosquitoes could affect their ability to deal with viral infections. This study confirms that the DENV and ZIKV infection patterns of nine Ae. aegypti field populations found in geographically separate health districts of an endemic Brazilian city vary. We analyzed the infection rate, disseminated infection, vector competence, and viral load through quantitative PCR. Mosquitoes were challenged using the membrane-feeding assay technique and were tested seven and fourteen days post-infection (early and late infection phases, respectively). The infection responses varied among the Ae. aegypti populations for both flaviviruses in the two infection phases. There was no similarity between DENV and ZIKV vector competencies or viral loads. According to the results of our study, the risk of viral transmission overtime after infection either increases or remains unaltered in ZIKV infected vectors. However, the risk may increase, decrease, or remain unaltered in DENV-infected vectors depending on the mosquito population. For both flaviviruses, the viral load persisted in the body even until the late infection phase. In contrast to DENV, the ZIKV accumulated in the SG over time in all the mosquito populations. These findings are novel and may help direct the development of control strategies to fight dengue and Zika outbreaks in endemic regions, and provide a warning about the importance of understanding mosquito responses to arboviral infections.

Vector Competence to Zika Virus Changes Depending on the Manaus's Region Origin of the <em>Aedes aegypti</em>: A Study of an Endemic Brazilian Amazonian City

“…Variations in IR and DIR among geographically diverse mosquito populations of the same species are observed in the literature for different arboviruses in Aedes spp. (7,10,(24)(25)(26). These results are in line with that made with Ae.…”

“…It was already demonstrated in previous studies that the infection parameters of Ae. aegypti after arbovirus challenge can vary in mosquitoes from distinct geographic areas (24), including that belonging to the same city (7,10), corroborating the results presented here for the field-derived populations of Ae. aegypti from Manaus.…”

“…These results are in line with that made with Ae. aegypti populations from the city of Belo Horizonte in Brazil (7), with high values of IR and DIR for ZIKV infections. A similar vector competence study was conducted in Manaus with 4 serotypes of DENV and demonstrated that the Ae.…”

“…The worldwide distribution of Ae. aegypti (10) and its permissiveness to ZIKV contribute to the broad range of regions at risk of Zika fever outbreaks, with the disease representing a recurring threat to the worldwide health system (7,11). The understanding of the dynamics of the Ae.…”

Evaluation of cutaneous immune response in a controlled human in vivo model of mosquito bites

“…Mosquitoes first acquire an arbovirus via insertion of their proboscis into the dermis of an infected host during a blood meal. The virus then replicates in midgut cells to later disseminate and reach the salivary glands (SG) 4 . During a subsequent blood meal, the infectious mosquito inoculates virus and insect-derived molecules, including salivary components, into the dermis of a new human host.…”